The goal of this project is to examine aspects of language behavior including semantic, syntactic, and metalinguistic skills, spontaneous speech, also nonverbal perceptual skills and cognition, in a sample of psychotic children aged 6-15 previously diagnosed as autistic or schizophrenic. Identical data is being collected on 3 control groups: children matched by mean length of utterance, children matched for perceptual skills, and children matched for chronological age. All children in the sample of 100 tested in Fall 1976 will be tested again in spring 1977 and fall 1977. Control group subjects will be tested once and matches to the psychotic sample will be based on the spring 1977 data. In addition, Rutter-based, Creak-based and Rimland diagnosis will be done on all children in the experimental group. These data together with the language skills data and data from nonverbal IQ measures and perceptual measures, will be analyzed with the hope of providing evidence towards resolving 4 current controversies: (1) are autism and schizophrenia a signle syndrome?; (2) what model do these data suggest as more plausible--cortical site damage or general dysfunction?; (3) are the language behaviors of psychotic children bizarre or normal but delayed?; and (4) are language behaviors critical for differential diagnosis and, if so, which behaviors are most critical?